The present disclosure relates to a fluidically controlled pressure switching valve for a vehicle brake system and to a corresponding vehicle brake system having a pressure switching valve of the kind described herein.
The prior art includes vehicle brake systems with vehicle dynamics control, e.g. ABS/TCS/ESP. A vehicle brake system as a technical system is used to ensure deceleration and prevention of rolling movements of a motor vehicle according to the requirements of the driver or according to the driving situation. Integrated vehicle dynamics control counteracts possible breakaway of the car by selective braking of individual wheels. From the sector of vehicle brake systems, a very wide variety of systems is known in which an active or partially active pressure buildup in the hydraulic unit is achieved by means of a two-stage high-pressure switching valve. When activated or actuated, the high-pressure switching valve opens a suction path from a brake master cylinder to a return pump. In general, the high-pressure switching valve is operated by means of a magnetic field produced by an electric coil.
German Offenlegungsschrift DE 10 2009 027 706 A1 has disclosed a fluidically controlled control valve for a vehicle brake system and a corresponding vehicle brake system. The control valve described comprises a valve chamber, which is arranged in a valve interior and into which an inlet opening and an outlet opening open, and a valve closing body, which is guided movably in the valve interior and which comprises a piston, having a first piston surface and a second piston surface, and a closing element, wherein the valve closing body can be moved in accordance with a pressure difference between a pressure acting on the first piston surface and a pressure acting on the second piston surface, against the force of a setting spring arranged in the valve interior, between a closed position, in which a fluid connection between the inlet opening and the outlet opening is interrupted, and an open position, in which the fluid connection between the inlet opening and the outlet opening is open, wherein the first piston surface delimits a first control chamber in the valve interior, which chamber is connected by at least one compensating connection to the outlet opening, wherein the second piston surface delimits a second control chamber, which chamber is connected by a pressure-relieved connection to the atmosphere, and wherein the second control chamber is separated from the valve chamber by a partition wall. Owing to the pressure-relieved connection to the atmosphere or the ambient pressure, external leakage, i.e. leakage to the outside, can occur.